The proposed research deals with the nutritional requirements for growth of B-16 melanoma. Dietary intake of tryosine, phenylalanine, and cysteine will be correlated with establishment of tumors and with treatment of established tumors in mice. Special amino acid diets containing a specified amount of the amino acid(s) in question will be fed to tumor bearing BDF1, female, mice. The anti-tumor effect of L-dopamethylester and carbidopa in combination with various nutritional manipulations of these amion acids will also be studied. The effect of the various treatments on lifespan in mice with ascites tumors will be determined and the effect of these treatments on the growth rate and survival of mice with subcutaneous tumors will be determined. The experiments with cysteine diets will provide information regarding the mechanism of action of L-dopamethylester in melanoma. Competition for uptake between tyrosine, phenylalanine, and 3H-L-dopamethylester will be determined by measuring the corporation of radioactivity into melanoma tumors and melanin using liquid scintillation counting.